Control channel design for shared wireless communications

ABSTRACT

Methods, systems, and devices for wireless communication are described that may enable a user equipment (UE) to monitor a shared spectrum to receive control signaling and data transmissions associated with different transmission time intervals (TTIs). For example, a base station may communicate with a UE according to a first transmission mode during a first, shortened TTI. The base station may transmit a downlink control channel for a shortened TTI based on a subset of a number of blind decodes or control channel elements. Additionally, a downlink control channel for a shortened TTI may contain grants for multiple TTIs. In some cases, the base station may transmit a signaling to the UE via a reference signal, downlink control channel, or radio resource control which may indicate a change from the shortened-TTI transmission mode to a transmission mode with a TTI duration that is longer than the first, shortened TTI duration.

CROSS REFERENCE

The present Application for Patent is a division of U.S. patentapplication Ser. No. 16/799,332 by SUN et al., entitled “CONTROL CHANNELDESIGN FOR SHARED WIRELESS COMMUNICATIONS,” filed Feb. 24, 2020 which isa continuation of U.S. patent application Ser. No. 16/733,176 by SUN etal., entitled “CONTROL CHANNEL DESIGN FOR SHARED WIRELESSCOMMUNICATIONS,” filed Jan. 2, 2020, which claims the benefit of U.S.Provisional Patent Application No. 62/788,530 by SUN et al., entitled“CONTROL CHANNEL DESIGN FOR SHARED WIRELESS COMMUNICATIONS,” filed Jan.4, 2019, each of which is assigned to the assignee hereof and expresslyincorporated herein.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to control channel design for shared wirelesscommunications.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

In some cases, a base station and UE operating in shared or unlicensedspectrum may participate in contention-based access procedures prior tobeginning communications (e.g., to determine whether resources areavailable for communication). After gaining access to resources forcommunication, a base station and a UE may communicate using varyingtransmission time intervals (e.g., slots, mini-slots, symbols).

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support control channel design for shared wirelesscommunications. Generally, the described techniques provide for enablinga user equipment (UE) to monitor a shared spectrum to receive controlsignaling and data transmissions associated with different sizes oftransmission time intervals (TTIs) (e.g., TTIs of varying durations).For example, a base station and a UE may monitor a channel of a sharedradio frequency spectrum band during a listen before talk (LBT)procedure to determine whether communication resources are available.After monitoring determining resources are available, the base stationmay transmit a downlink control channel to the UE according to a firsttransmission mode (e.g., a mini-slot transmission mode) during a firstTTI (e.g., a shortened TTI (sTTI)). In some examples, the downlinkcontrol channel may indicate respective grants for each of a set of TTIsincluding a second TTI subsequent to the first TTI. Additionally oralternatively, the base station may transmit a signaling to the UEindicating a change from the first transmission mode (e.g., a mini-slotbased transmission mode) to a second transmission mode (e.g., slot basedtransmission mode). In some examples, the signaling indicating a changemay be transmitted via a reference signal, a control channel, or a radioresource control (RRC) message, among others, and may indicate thebeginning of communications according to the second transmission mode.

A method of wireless communications at a UE is described. The method mayinclude monitoring a shared radio frequency spectrum band for a downlinkcontrol channel from a base station during a first TTI according to afirst transmission mode, receiving, from the base station, signalingindicating a change from the first transmission mode to a secondtransmission mode, the first transmission mode associated with a firstTTI duration and the second transmission mode associated with a secondTTI duration that is longer than the first TTI duration, and monitoringthe shared radio frequency spectrum band for the downlink controlchannel from the base station during a second TTI based on thesignaling.

An apparatus for wireless communications at a UE is described. Theapparatus may include a processor, memory coupled with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to monitor a sharedradio frequency spectrum band for a downlink control channel from a basestation during a first TTI according to a first transmission mode,receive, from the base station, signaling indicating a change from thefirst transmission mode to a second transmission mode, the firsttransmission mode associated with a first TTI duration and the secondtransmission mode associated with a second TTI duration that is longerthan the first TTI duration, and monitor the shared radio frequencyspectrum band for the downlink control channel from the base stationduring a second TTI based on the signaling.

Another apparatus for wireless communications at a UE is described. Theapparatus may include means for monitoring a shared radio frequencyspectrum band for a downlink control channel from a base station duringa first TTI according to a first transmission mode, receiving, from thebase station, signaling indicating a change from the first transmissionmode to a second transmission mode, the first transmission modeassociated with a first TTI duration and the second transmission modeassociated with a second TTI duration that is longer than the first TTIduration, and monitoring the shared radio frequency spectrum band forthe downlink control channel from the base station during a second TTIbased on the signaling.

A non-transitory computer-readable medium storing code for wirelesscommunications at a UE is described. The code may include instructionsexecutable by a processor to monitor a shared radio frequency spectrumband for a downlink control channel from a base station during a firstTTI according to a first transmission mode, receive, from the basestation, signaling indicating a change from the first transmission modeto a second transmission mode, the first transmission mode associatedwith a first TTI duration and the second transmission mode associatedwith a second TTI duration that is longer than the first TTI duration,and monitor the shared radio frequency spectrum band for the downlinkcontrol channel from the base station during a second TTI based on thesignaling.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the signaling mayinclude operations, features, means, or instructions for receiving areference signal that indicates a beginning of communications accordingto the second transmission mode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for monitoring the sharedradio frequency spectrum band during a remaining portion of the firstTTI based on receiving the reference signal during the first portion ofthe first TTI.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the second TTI includes thebeginning of communications according to the second transmission mode.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the signaling mayinclude operations, features, means, or instructions for receiving aphysical downlink control channel (PDCCH) from the base station, thePDCCH including a switching indicator that indicates one or more of abeginning of communications according to the second transmission mode ora continuation of communications according to the first transmissionmode.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the signaling mayinclude operations, features, means, or instructions for receiving anRRC message from the base station, the RRC message indicating a fixednumber of TTIs for communications according to the first transmissionmode before the change from the first transmission mode to the secondtransmission mode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a maximumnumber of blind decodes for the downlink control channel and a maximumnumber of control channel elements (CCEs) for the downlink controlchannel, where the maximum total number of blind decodes and the maximumnumber of CCEs may be distributed among TTIs of the first transmissionmode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving the downlinkcontrol channel according to the first transmission mode during thefirst TTI based on a first subset of the maximum number of blind decodesand a first subset of the maximum number of CCEs.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving the downlinkcontrol channel according to the first transmission mode during thesecond TTI based on a second subset of the maximum number of blinddecodes and a second subset of the maximum number of CCEs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first subset of themaximum number of blind decodes and the second subset of the maximumnumber of blind decodes may be the same, and the first subset of themaximum number of CCEs and the second subset of the maximum number ofCCEs may be the same.

A method of wireless communications at a base station is described. Themethod may include monitoring a channel of a shared radio frequencyspectrum band during an LBT procedure, the channel associated withcommunications between the base station and a UE, transmitting adownlink control channel to the UE according to a first transmissionmode during a first TTI based on the monitoring, and transmitting, tothe UE, signaling indicating a change from the first transmission modeto a second transmission mode, the first transmission mode associatedwith a first TTI duration and the second transmission mode associatedwith a second TTI duration that is longer than the first TTI duration.

An apparatus for wireless communications at a base station is described.The apparatus may include a processor, memory coupled with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to monitor achannel of a shared radio frequency spectrum band during a listen beforetalk procedure, the channel associated with communications between thebase station and a UE, transmit a downlink control channel to the UEaccording to a first transmission mode during a first TTI based on themonitoring, and transmit, to the UE, signaling indicating a change fromthe first transmission mode to a second transmission mode, the firsttransmission mode associated with a first TTI duration and the secondtransmission mode associated with a second TTI duration that is longerthan the first TTI duration.

Another apparatus for wireless communications at a base station isdescribed. The apparatus may include means for monitoring a channel of ashared radio frequency spectrum band during a listen before talkprocedure, the channel associated with communications between the basestation and a UE, transmitting a downlink control channel to the UEaccording to a first transmission mode during a first TTI based on themonitoring, and transmitting, to the UE, signaling indicating a changefrom the first transmission mode to a second transmission mode, thefirst transmission mode associated with a first TTI duration and thesecond transmission mode associated with a second TTI duration that islonger than the first TTI duration.

A non-transitory computer-readable medium storing code for wirelesscommunications at a base station is described. The code may includeinstructions executable by a processor to monitor a channel of a sharedradio frequency spectrum band during a listen before talk procedure, thechannel associated with communications between the base station and aUE, transmit a downlink control channel to the UE according to a firsttransmission mode during a first TTI based on the monitoring, andtransmit, to the UE, signaling indicating a change from the firsttransmission mode to a second transmission mode, the first transmissionmode associated with a first TTI duration and the second transmissionmode associated with a second TTI duration that is longer than the firstTTI duration.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the signalingmay include operations, features, means, or instructions fortransmitting a reference signal that indicates a beginning ofcommunications according to the second transmission mode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thereference signal during a first portion of the first TTI, andtransmitting a single downlink control channel during a remainingportion of the first TTI based on transmitting the reference signalduring the first portion of the first TTI.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a second TTI subsequent thefirst TTI includes the beginning of communications according to thesecond transmission mode.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the signalingmay include operations, features, means, or instructions fortransmitting a PDCCH to the UE, the PDCCH including a switchingindicator that indicates one or more of a beginning of communicationsaccording to the second transmission mode or a continuation ofcommunications according to the first transmission mode.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the signalingmay include operations, features, means, or instructions fortransmitting an RRC message to the UE, the RRC message indicating afixed number of TTIs for communications according to the firsttransmission mode before the change from the first transmission mode tothe second transmission mode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a maximumnumber of blind decodes for the downlink control channel and a maximumnumber of CCEs for the downlink control channel, where the maximumnumber of blind decodes and the maximum number of CCEs may bedistributed among TTIs of the first transmission mode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thedownlink control channel according to the first transmission mode duringthe first TTI based on a first subset of the maximum number of blinddecodes and a first subset of the maximum number of CCEs.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thedownlink control channel according to the first transmission mode duringa second TTI subsequent the first TTI based on a second subset of themaximum number of blind decodes and a second subset of the maximumnumber of CCEs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first subset of themaximum number of blind decodes and the second subset of the maximumnumber of blind decodes may be the same, and the first subset of themaximum number of CCEs and the second subset of the maximum number ofCCEs may be the same.

A method of wireless communications at a UE is described. The method mayinclude monitoring a shared radio frequency spectrum band for a downlinkcontrol channel from a base station during a first TTI, receiving thedownlink control channel from the base station during the first TTIbased on the monitoring, the downlink control channel indicatingrespective grants for each of a set of TTIs including a second TTIsubsequent the first TTI, and receiving one or more downlink datatransmissions over the set of TTIs in accordance with the respectivegrants.

An apparatus for wireless communications at a UE is described. Theapparatus may include a processor, memory coupled with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to monitor a sharedradio frequency spectrum band for a downlink control channel from a basestation during a first TTI, receive the downlink control channel fromthe base station during the first TTI based on the monitoring, thedownlink control channel indicating respective grants for each of a setof TTIs including a second TTI subsequent the first TTI, and receive oneor more downlink data transmissions over the set of TTIs in accordancewith the respective grants.

Another apparatus for wireless communications at a UE is described. Theapparatus may include means for monitoring a shared radio frequencyspectrum band for a downlink control channel from a base station duringa first TTI, receiving the downlink control channel from the basestation during the first TTI based on the monitoring, the downlinkcontrol channel indicating respective grants for each of a set of TTIsincluding a second TTI subsequent the first TTI, and receiving one ormore downlink data transmissions over the set of TTIs in accordance withthe respective grants.

A non-transitory computer-readable medium storing code for wirelesscommunications at a UE is described. The code may include instructionsexecutable by a processor to monitor a shared radio frequency spectrumband for a downlink control channel from a base station during a firstTTI, receive the downlink control channel from the base station duringthe first TTI based on the monitoring, the downlink control channelindicating respective grants for each of a set of TTIs including asecond TTI subsequent the first TTI, and receive one or more downlinkdata transmissions over the set of TTIs in accordance with therespective grants.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving the downlinkcontrol channel in a shared data portion of the first TTI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving the downlinkcontrol channel before a shared data portion of the second TTIsubsequent the first TTI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining the set ofTTIs based on the monitoring, where the set of TTIs includes TTIsexcluding the first TTI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a maximumnumber of blind decodes for the downlink control channel and a maximumnumber of CCEs for the downlink control channel, where the downlinkcontrol channel may be received based on the maximum number of blinddecodes and the maximum number of CCEs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the maximum number of blinddecodes and the maximum number of CCEs may be based on a number of TTIsof the set of TTIs.

A method of wireless communications is described. The method may includemonitoring a channel of a shared radio frequency spectrum band during anLBT procedure, the channel associated with communications between a basestation and a UE, transmitting a downlink control channel to the UEduring a first TTI based on the monitoring, the downlink control channelindicating respective grants for each of a set of TTIs including asecond TTI subsequent the first TTI, and transmitting one or moredownlink data transmissions to the UE over the set of TTIs in accordancewith the respective grants.

An apparatus for wireless communications is described. The apparatus mayinclude a processor, memory coupled with the processor, and instructionsstored in the memory. The instructions may be executable by theprocessor to cause the apparatus to monitor a channel of a shared radiofrequency spectrum band during a listen before talk procedure, thechannel associated with communications between a base station and a UE,transmit a downlink control channel to the UE during a first TTI basedon the monitoring, the downlink control channel indicating respectivegrants for each of a set of TTIs including a second TTI subsequent thefirst TTI, and transmit one or more downlink data transmissions to theUE over the set of TTIs in accordance with the respective grants.

Another apparatus for wireless communications is described. Theapparatus may include means for monitoring a channel of a shared radiofrequency spectrum band during a listen before talk procedure, thechannel associated with communications between a base station and a UE,transmitting a downlink control channel to the UE during a first TTIbased on the monitoring, the downlink control channel indicatingrespective grants for each of a set of TTIs including a second TTIsubsequent the first TTI, and transmitting one or more downlink datatransmissions to the UE over the set of TTIs in accordance with therespective grants.

A non-transitory computer-readable medium storing code for wirelesscommunications is described. The code may include instructionsexecutable by a processor to monitor a channel of a shared radiofrequency spectrum band during a listen before talk procedure, thechannel associated with communications between a base station and a UE,transmit a downlink control channel to the UE during a first TTI basedon the monitoring, the downlink control channel indicating respectivegrants for each of a set of TTIs including a second TTI subsequent thefirst TTI, and transmit one or more downlink data transmissions to theUE over the set of TTIs in accordance with the respective grants.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thedownlink control channel in a shared data portion of the first TTI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thedownlink control channel before a shared data portion of the second TTIsubsequent the first TTI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining the set ofTTIs based on the monitoring, where the set of TTIs includes TTIsexcluding the first TTI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a maximumnumber of blind decodes for the downlink control channel and a set ofCCEs for the downlink control channel, where the downlink controlchannel may be transmitted based on the maximum number of blind decodesand the set of CCEs.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the maximum number of blinddecodes and the set of CCEs may be based on a number of TTIs of the setof TTIs.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thedownlink control channel via a first subset of the CCEs during the firstTTI, and transmitting the downlink control channel via a second subsetof the CCEs during the second TTI.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system thatsupports control channel design for shared wireless communications inaccordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system thatsupports control channel design for shared wireless communications inaccordance with aspects of the present disclosure.

FIGS. 3 and 4 illustrate examples of resource schedules that supportcontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure.

FIG. 5 illustrates an example of a process flow that supports controlchannel design for shared wireless communications in accordance withaspects of the present disclosure.

FIGS. 6 and 7 show block diagrams of devices that support controlchannel design for shared wireless communications in accordance withaspects of the present disclosure.

FIG. 8 shows a block diagram of a communications manager that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure.

FIG. 9 shows a diagram of a system including a device that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure.

FIGS. 10 and 11 show block diagrams of devices that support controlchannel design for shared wireless communications in accordance withaspects of the present disclosure.

FIG. 12 shows a block diagram of a communications manager that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure.

FIG. 13 shows a diagram of a system including a device that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure.

FIGS. 14 through 17 show flowcharts illustrating methods that supportcontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure.

DETAILED DESCRIPTION

Wireless communications devices operating in shared or unlicensedspectrum on a New Radio (NR) network may use contention-based proceduresto begin communications using the shared or unlicensed spectrum. Forexample, a base station may employ a listen before talk (LBT) procedureto determine whether a set of resources is available for transmission.Following a successful contention-based procedure (e.g., LBT), a basestation may utilize transmission time intervals (TTIs) of varyingdurations (slots, mini-slots, symbols, etc.) to begin transmissions to auser equipment (UE). In some cases, the use of shortened TTIs (sTTIs)may allow a base station to avoid wasting time-frequency resourcesbetween the point the communications pass the contention-based procedureand the point at which a next slot begins. In some examples, mini-slotbased transmissions may continue up until a given slot boundary, where abase station may switch to slot-based transmissions. In some cases, thebase station may choose when to switch to slot-based transmissions basedon the capabilities of the base station (e.g., data preparationcapabilities). For example, a base station may wait a number of slotsafter passing the contention-based procedure to switch to slot-basedtransmissions.

In order to switch between transmission types (e.g., between mini-slotbased and slot-based transmissions), a base station may notify a UE whenthe switch is to occur. For example, a base station may send a dedicatedphysical layer signal (e.g., a reference signal) to a UE as part of themini-slot based transmissions. In some cases, the dedicated signal mayinclude information as to when the switch is to occur (e.g., the nextslot is to be a slot-based transmission). Additionally or alternatively,the dedicated signal may include a notification that the remainder ofthe slot following the signal is no longer to be split into mini-slotsand the portion of the slot following the dedicated signal may be takenup by one mini-slot (e.g., instead of multiple mini-slots), followed bya slot at the next slot boundary. In other examples, a base station mayinclude information regarding the switch to slot-based transmissions aspart of a physical downlink control channel (PDCCH) associated with themini-slot or slot-based transmissions. For example, a UE may decode aPDCCH associated with mini-slot based transmissions and obtain thetiming of the switch to slot-based transmissions.

Additionally or alternatively, a base station and a UE may have implicitunderstanding of when to make the switch to slot-based transmissions. Insome cases, a base station and a UE may be configured (e.g., via radioresource control (RRC) signaling or as part of a standard) to determinehow long to transmit or receive mini-slot based transmissions. Forexample, a base station and a UE may be configured such that after thefirst mini-slot based transmission, the base station and UE are tocommunicate according to a given number of slots or mini-slots untilslot-based transmissions begin.

In some examples, a UE may be limited to a number (e.g., a total ormaximum number) of blind decodes or control channel elements (CCEs) a UEis to process on the PDCCH associated with mini-slot basedtransmissions. In some cases, the limit associated with a PDCCH of onemini-slot may be a subset of the limit associated with the PDCCH of oneslot. For example, the limit of blind decodes or CCEs for a slot may beequally split among mini-slots occupying the same time frame as theslot. Additionally or alternatively, the per slot limit of blind decodesor CCEs for a UE to decode may be split among mini-slots proportional toa number of symbols each mini-slot occupies in comparison to the numberof symbols the slot occupies.

In some cases, the PDCCH associated with mini-slot based transmissionsmay be a multi-grant PDCCH, where the multi-grant PDCCH may carry grantinformation pertaining to one or more mini-slots. For example, a UE maydecode a multi-grant PDCCH and obtain grants for all mini-slots in agiven slot. Additionally or alternatively, a UE may decode a multi-grantPDCCH and obtain grant information for a number of mini-slots which mayextend past a slot boundary and into a subsequent slot. In some cases, aUE may determine not to decode further PDCCH instances for mini-slottransmissions after decoding a first PDCCH (e.g., because the PDCCH maycontain grants for all following mini-slots).

Aspects of the disclosure are initially described in the context ofwireless communications systems. Aspects of the disclosure are furtherillustrated by and described with reference to resource schedules, aprocess flow, apparatus diagrams, system diagrams, and flowcharts thatrelate to control channel design for shared wireless communications.

FIG. 1 illustrates an example of a wireless communications system 100that supports control channel design for shared wireless communicationsin accordance with aspects of the present disclosure. The wirelesscommunications system 100 includes base stations 105, UEs 115, and acore network 130. In some examples, the wireless communications system100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A)network, an LTE-A Pro network, or a New Radio (NR) network. In somecases, wireless communications system 100 may support enhanced broadbandcommunications, ultra-reliable (e.g., mission critical) communications,low latency communications, or communications with low-cost andlow-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples,half-duplex communications may be performed at a reduced peak rate.Other power conservation techniques for UEs 115 include entering a powersaving “deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that may be capable of toleratinginterference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ LBT procedures to ensure a frequencychannel is clear before transmitting data. In some cases, operations inunlicensed bands may be based on a carrier aggregation configuration inconjunction with component carriers operating in a licensed band (e.g.,LAA). Operations in unlicensed spectrum may include downlinktransmissions, uplink transmissions, peer-to-peer transmissions, or acombination of these. Duplexing in unlicensed spectrum may be based onfrequency division duplexing (FDD), time division duplexing (TDD), or acombination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving device is equipped with one or moreantennas. MIMO communications may employ multipath signal propagation toincrease the spectral efficiency by transmitting or receiving multiplesignals via different spatial layers, which may be referred to asspatial multiplexing. The multiple signals may, for example, betransmitted by the transmitting device via different antennas ordifferent combinations of antennas. Likewise, the multiple signals maybe received by the receiving device via different antennas or differentcombinations of antennas. Each of the multiple signals may be referredto as a separate spatial stream, and may carry bits associated with thesame data stream (e.g., the same codeword) or different data streams.Different spatial layers may be associated with different antenna portsused for channel measurement and reporting. MIMO techniques includesingle-user MIMO (SU-MIMO) where multiple spatial layers are transmittedto the same receiving device, and multiple-user MIMO (MU-MIMO) wheremultiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g., synchronizationsignals, reference signals, beam selection signals, or other controlsignals) may be transmitted by a base station 105 multiple times indifferent directions, which may include a signal being transmittedaccording to different beamforming weight sets associated with differentdirections of transmission. Transmissions in different beam directionsmay be used to identify (e.g., by the base station 105 or a receivingdevice, such as a UE 115) a beam direction for subsequent transmissionand/or reception by the base station 105.

Some signals, such as data signals associated with a particularreceiving device, may be transmitted by a base station 105 in a singlebeam direction (e.g., a direction associated with the receiving device,such as a UE 115). In some examples, the beam direction associated withtransmissions along a single beam direction may be determined based on asignal that was transmitted in different beam directions. For example, aUE 115 may receive one or more of the signals transmitted by the basestation 105 in different directions, and the UE 115 may report to thebase station 105 an indication of the signal received by the UE 115 witha highest signal quality, or an otherwise acceptable signal quality.Although these techniques are described with reference to signalstransmitted in one or more directions by a base station 105, a UE 115may employ similar techniques for transmitting signals multiple times indifferent directions (e.g., for identifying a beam direction forsubsequent transmission or reception by the UE 115), or transmitting asignal in a single direction (e.g., for transmitting data to a receivingdevice).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based on listeningaccording to different receive beam directions (e.g., a beam directiondetermined to have a highest signal strength, highest signal-to-noiseratio, or otherwise acceptable signal quality based on listeningaccording to multiple beam directions).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer mayperform packet segmentation and reassembly to communicate over logicalchannels. A Medium Access Control (MAC) layer may perform priorityhandling and multiplexing of logical channels into transport channels.The MAC layer may also use hybrid automatic repeat request (HARQ) toprovide retransmission at the MAC layer to improve link efficiency. Inthe control plane, the Radio Resource Control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and a base station 105 or core network 130supporting radio bearers for user plane data. At the Physical layer,transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a TTI. In other cases, a smallest scheduling unitof the wireless communications system 100 may be shorter than a subframeor may be dynamically selected (e.g., in bursts of sTTIs or in selectedcomponent carriers using sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an evolved universal mobiletelecommunication system terrestrial radio access (E-UTRA) absoluteradio frequency channel number (EARFCN)), and may be positionedaccording to a channel raster for discovery by UEs 115. Carriers may bedownlink or uplink (e.g., in an FDD mode), or be configured to carrydownlink and uplink communications (e.g., in a TDD mode). In someexamples, signal waveforms transmitted over a carrier may be made up ofmultiple sub-carriers (e.g., using multi-carrier modulation (MCM)techniques such as orthogonal frequency division multiplexing (OFDM) ordiscrete Fourier transform spread OFDM (DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information, etc.) and control signaling thatcoordinates operation for the carrier. In some examples (e.g., in acarrier aggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or resource blocks (RBs)) within a carrier (e.g., “in-band”deployment of a narrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation or multi-carrier operation. A UE 115 may beconfigured with multiple downlink component carriers and one or moreuplink component carriers according to a carrier aggregationconfiguration. Carrier aggregation may be used with both FDD and TDDcomponent carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than othercomponent carriers, which may include use of a reduced symbol durationas compared with symbol durations of the other component carriers. Ashorter symbol duration may be associated with increased spacing betweenadjacent subcarriers. A device, such as a UE 115 or base station 105,utilizing eCCs may transmit wideband signals (e.g., according tofrequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) atreduced symbol durations (e.g., 16.67 microseconds). A TTI in eCC mayconsist of one or multiple symbol periods. In some cases, the TTIduration (that is, the number of symbol periods in a TTI) may bevariable.

Wireless communications system 100 may be an NR system that may utilizeany combination of licensed, shared, and unlicensed spectrum bands,among others. The flexibility of eCC symbol duration and subcarrierspacing may allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossthe frequency domain) and horizontal (e.g., across the time domain)sharing of resources.

Wireless communications devices operating in shared or unlicensedspectrum on an NR network may use contention-based procedures to begincommunications on the shared or unlicensed spectrum. For example, a basestation 105 may employ an LBT mechanism to monitor a wireless channeland determine whether the base station has gained access to the channel.Following a successful contention-based procedure (e.g., LBT), a basestation 105 may begin a transmission opportunity and communicate with aUE 115. In some cases, at a beginning of communications, a base station105 may immediately schedule transmission in a partial slot that may beavailable before the next slot boundary. In some examples, slots may bepre-configured with a number of concatenated mini-slots which may beused for communications in the partial slot, and a base station 105 mayuse these mini-slots to begin communications with a UE 115.

Additionally, a gap between the end of the contention-based procedureand the beginning of an available mini-slot may be filled with a fillersignal or filler energy to hold the wireless channel for communicationsbetween the base station 105 and the UE 115. In some examples, mini-slottransmissions may continue up until a given slot boundary, where thebase station 105 may switch to slot-based transmissions. In some cases,a base station 105 may provide a PDCCH configuration for both mini-slotand slot-based transmissions, which a UE 115 may monitor for a grant forthe respective transmissions. The base station 105 may switch toslot-based transmissions in order to reduce overhead due to additionalPDCCH monitoring occasions for mini-slots. Therefore, a base station 105may switch to slot-based transmissions as soon as the base station canprepare the resources for transmission.

In some cases, a base station 105 may be unaware of when acontention-based procedure may pass, and may therefore prepare dataspanning an entire slot or mini-slot as well as corresponding grants(e.g., via PDCCH). In some examples, a base station 105 may have tocancel prepared data if the contention-based procedure does not passbefore the slot or mini-slot containing the prepared data. As such, abase station 105 may postpone some data it has prepared, and may beunable to postpone the data to an immediately subsequent slot ormini-slot (e.g., due to latency involved in data preparation in bothphysical layers and higher layers). Therefore, a base station 105 mayreschedule canceled data to a future mini-slot or slot transmission,based on the capabilities of the base station 105 (e.g., datapreparation capabilities). A UE 115 may be unaware of when acontention-based procedure may pass and may therefore monitor for agrant at a control region corresponding to each mini-slot in theresources used for communication with a base station 105. In someexamples, a UE 115 may also be unaware of when the switch from mini-slottransmissions to slot-based transmissions is to occur, and a basestation 105 may therefore signal a UE 115 with information regardingwhen the switch is to occur.

In order to switch between transmission types (e.g., mini-slot based andslot-based transmissions), a base station 105 may notify a UE 115 whenthe switch from mini-slot based transmissions (e.g., a firsttransmission mode) to slot-based transmissions (e.g., a secondtransmission mode) is to occur. For example, a base station may send adedicated signal (e.g., a reference signal) to a UE as part of mini-slotbased transmissions. In other examples, a base station 105 may includeinformation regarding the switch to slot-based transmissions as part ofa PDCCH associated with the mini-slot or slot-based transmissions. Insome cases, a PDCCH associated with mini-slot transmissions may have alimit of blind decodes or CCEs for the UE to process, where the limit isbased on the size of a given mini-slot compared to the size of a slot.In some examples, a PDCCH associated with mini-slot based transmissionsmay be a multi-grant PDCCH and may carry grant information regarding oneor more mini-slots. Additionally or alternatively, a base station 105and a UE 115 may be configured to implicitly determine when the switchfrom mini-slot based to slot-based transmissions is to occur.

FIG. 2 illustrates an example of a wireless communications system 200that supports control channel design for shared wireless communicationsin accordance with aspects of the present disclosure. In some examples,wireless communications system 200 may implement aspects of wirelesscommunication system 100 and may include a UE 115-a and a base station105-a, which may be examples of a UE 115 and a base station 105described with reference to FIG. 1 . UE 115-a and base station 105-a maycommunicate using a shared spectrum (e.g., unlicensed spectrum). In somecases, UE 115-a and base station 105-a may employ a contention-basedaccess procedure (e.g., LBT procedure) to begin communications, afterwhich the devices may communicate using sTTIs (e.g., mini-slots).Additionally, after communicating using mini-slots for a given timeperiod, base station 105-a and UE 115-a may switch to slot-basedcommunications.

For example, base station 105-a and UE 115-a may communicate with eachother using a shared (e.g., unlicensed) spectrum, and base station 105-amay employ an LBT procedure to begin communications with UE 115-a usinga channel of the shared spectrum. In some cases, the LBT procedure mayinclude an LBT period 205, where base station 105-a may monitor for openor unused resources. In some examples, base station 105-a may detect anLBT pass 225 by determining that no other signals currently occupy theresources the base station is monitoring. Base station 105-a may thentransmit a filler signal 210 to UE 115-a in order to hold the resourcesfor transmission until the next mini-slot boundary 230, where basestation 105-a may begin mini-slot transmissions 215. In some cases,mini-slot transmissions 215 may span less than one slot and mayterminate at a first slot boundary 235-a. Additionally or alternatively,mini-slot transmissions 215 may span more than one slot and mayterminate at a later slot boundary 235 (e.g., slot boundary 235-b). Insome examples, a duration of mini-slot transmissions may be based oncapabilities of base station 105-a (e.g., data preparation, latency,etc.).

In some cases, base station 105-a may indicate an end of mini-slottransmissions 215 (e.g., a first transmission mode) and a beginning ofslot transmissions 220 (e.g., a second transmission mode) using aTTI-specific control signal (e.g., slot indication signal 240). In someexamples, slot indication signal 240 may be a dedicated signaltransmitted within mini-slot transmissions 215. In other examples, basestation 105-a may include slot indication signal 240 as part of PDCCHtransmissions to UE 115-a. Additionally or alternatively, wirelesscommunications system 200 may employ a configuration (e.g., RRCconfiguration) in which base station 105-a and UE 115-a determine atotal amount of mini-slot transmissions 215 to be used forcommunications after an LBT pass and before switching to slottransmissions 220 (e.g., during each transmission opportunity).

According to some aspects, base station 105-a may transmit a slotindication signal 240 any time previous to the beginning of slottransmissions 220 (e.g., as a part of mini-slot transmissions 215). Slotindication signal 240 may indicate a specific point at which slottransmissions 220 are to begin. Additionally or alternatively, basestation 105-a may transmit slot indication signal 240 as an initialslot-based signal, indicating the beginning of slot transmissions 220.As such, if UE 115-a were to receive slot indication signal 240 in themiddle of a slot, the signal may indicate a remainder of the slot is nolonger to be partitioned into mini-slots. Additionally or alternatively,reception of slot indication signal 240 may indicate that base station105-a is to transmit the subsequent slot using slot transmissions 220,where the remainder of the current slot may be partitioned intomini-slots. In some examples, base station 105-a may use any physicallayer signal (e.g., a reference signal) as the dedicated slot indicationsignal 240.

In one example of a configuration (e.g., RRC configuration) indicatingthe amount of mini-slot transmissions 215, base station 105-a and UE115-a may be previously configured (e.g., via RRC signaling or as partof a communications standard) to determine the amount of mini-slottransmissions 215 after communications begin. For example, afterdetecting the first mini-slot based transmission, UE 115-a may determinethat base station 105-a is to transmit a specified number of mini-slotsor slots (e.g., a configurable timer) before switching to slottransmissions 220. In some cases, the number of mini-slots or slotsbefore switching to slot transmissions 220 may be zero. In some cases,UE 115-a may restart the timer (e.g., may count another specified numberof slots or mini-slots) if UE 115-a receives a PDCCH from base station105-a before an end of the timer (e.g., before an end of the specifiednumber of slots or mini-slots).

In another example, base station 105-a may transmit slot indicationsignal 240 as a mode switching indicator in a PDCCH associated withmini-slot transmissions 215 or with slot transmissions 220. As such, UE115-a may decode the PDCCH to discover when slot transmissions 220 areto begin. For example, base station 105-a may include slot indicationsignal 240 as a binary mode switching indicator in a PDCCH. In somecases, the indicator may be a “1”, which may indicate that base station105-a has stopped mini-slot transmissions 215 and an entire next slot isto be occupied by slot transmissions 220. In other cases, the indicatormay be a “0”, which may indicate that base station 105-a is still usingmini-slot transmissions 215. In some examples, the function of thesebinary indicators may be reversed.

In some cases, base station 105-a may transmit multiple grants (e.g.,for multiple UEs 115) corresponding to mini-slot transmissions 215 usinga PDCCH in the same control region. In some examples, the multiplegrants may be carried by one PDCCH associated with mini-slottransmissions 215 (e.g., as a multi-grant PDCCH), where the multi-grantPDCCH may contain grant information for one or more mini-slots withinmini-slot transmissions 215. In some cases, base station 105-a maytransmit a multi-grant PDCCH before a corresponding physical downlinkshared channel (PDSCH) (e.g., at an end of a previous PDSCH).Additionally or alternatively, base station 105-a may transmit a PDCCHtogether with the corresponding PDSCH (e.g., within a first mini-slot).In some cases, base station 105-a may transmit a multi-grant PDCCH onceafter LBT pass 225, where the PDCCH may contain multiple grants formultiple PDSCH transmissions in mini-slot transmissions 215. In someexamples, a multi-grant PDCCH may contain grant information forcontiguous or non-contiguous mini-slots within mini-slot transmissions215. In some cases, a multi-grant PDCCH may carry a grant for allmini-slots in a remainder of a slot after LBT pass 225 (e.g., formini-slot transmissions 215 up to slot boundary 235-a). Additionally oralternatively, a multi-grant PDCCH may carry grant information for anumber of mini-slots that may extend to a subsequent slot (e.g., formini-slot transmissions 215 up to and past slot boundary 235-a).

In some cases, a PDCCH associated with slot transmissions 220 ormini-slot transmissions 215 may correspond to a respective controlmonitoring pattern of a per slot limit of blind decodes or CCEs for UE115-a to process. In some cases, UE 115-a may be configured to follow apattern that splits the limit of CCEs or blind decodes across a group ofmini-slots within a slot, based on a comparative size of the mini-slotand the slot. In some examples, UE 115-a may portion the per slot limitby splitting the limit equally among mini-slots within the slot.Additionally or alternatively, UE 115-a may split the per slot limitamong mini-slots in proportion to a number of symbols allocated to eachmini-slot, compared to a number of symbols allocated to the entire slot.In the case where mini-slot scheduling may end before a last mini-slotof the slot, the remainder of any blind decode or CCE limit may beallocated to a remaining portion of the slot.

FIG. 3 illustrates examples of resource schedules 301, 302, 303, and 304that support control channel design for shared wireless communicationsin accordance with aspects of the present disclosure. In some examples,resource schedules 301, 302, 303, and 304 may implement aspects ofwireless communications systems 100 or 200. A resource schedule 300(e.g., one of resource schedules 301, 302, 303, and 304) may includecommunications transmitted by a base station 105, which may be anexample of a base station 105 described with reference to FIGS. 1 and 2. Additionally, a UE 115 may receive the communications transmitted bythe base station 105, which UE may be an example of a UE 115 describedwith reference to FIGS. 1 and 2 .

As mentioned above with reference to FIGS. 1 and 2 , the base station105 may perform a contention-based access procedure (e.g., LBT) to gainaccess to shared network resources (e.g., unlicensed spectrum),following which the base station 105 may begin transmissions to the UE115 using shortened-TTI (e.g., mini-slot) resources. In some cases, thebase station 105 may prepare a resource schedule 300 before passing theLBT procedure. For example, the base station 105 may prepare mini-slots305 for communications that are to take place with the UE 115 followingan LBT pass. However, in some cases, neither the base station 105 northe UE 115 may be aware of when the LBT pass may occur. Therefore, thebase station 105 may modify resource schedule 300, where themodification may be based on capabilities of the base station 105.

For example, the LBT pass may occur within a first mini-slot 305-aprepared for transmission, and the base station 105 may have prepared aresource schedule similar to resource schedule 302. As such, the basestation 105 may not transmit data in mini-slot 305-a and may cancel andreschedule the data for a future mini-slot 305 or a future slot 310. Insome cases, the base station 105 may implement resource schedule 301(e.g., based on the capabilities of the base station 105), where thebase station 105 may reschedule data from mini-slot 305-a into mini-slot305-b, mini-slot 305-c, or slot 310-a.

Additionally or alternatively, the base station 105 may also signal thebeginning of slot-based transmissions before mini-slot 305-c, wheremini-slot 305-c may therefore be the last mini-slot based transmission(e.g., as illustrated with reference to resource schedule 301). Asdescribed herein, a signal used to indicate the beginning of slot-basedtransmissions may be a dedicated signal within mini-slot 305-b or at abeginning of mini-slot 305-c, or may be included in a PDCCH 315-b or315-c. Additionally or alternatively, the base station 105 and the UE115 may determine (e.g., implicitly) a number of mini-slots 305 that mayfollow the first mini-slot transmission based on a shared configuration(e.g., implemented via RRC signaling or communications standards). Insome cases, mini-slot 305-c may include more resources than othermini-slots 305, based on the end of the mini-slot based transmissions.

In some cases, based on its capabilities, the base station 105 mayimplement resource schedule 302, where the base station 105 mayreschedule data from mini-slot 305-a into mini-slot 305-b, mini-slot305-c, mini-slot 305-d, or slot 310-a. Additionally or alternatively,the base station 105 may also signal the beginning of slot-basedtransmissions before slot 310-a, where mini-slot 305-d may be the lastmini-slot based transmission. As described with reference to FIGS. 1 and2 , a signal to indicate the beginning of slot-based transmissions maybe a dedicated signal (e.g., a reference signal) within mini-slots305-b, 305-c, or 305-d, or may be a dedicated signal at a beginning ofslot 310-a. In some cases, reception of a dedicated signal may indicatethat the base station 105 is to transmit the subsequent slot 310-a usingslot-based transmissions, where a remainder of the current slot 310 maystill be partitioned into mini-slots 305. Additionally or alternatively,the signal to indicate the beginning of slot-based transmissions may beincluded in a PDCCH 315-b, 315-c, 315-d, or 315-e. In other cases, thebase station 105 and the UE 115 may determine the number of mini-slots305 that follow the first mini-slot transmission based on a sharedconfiguration (e.g., implemented via RRC signaling or communicationsstandards).

In some cases, the capabilities of the base station 105 may support theimplementation of resource schedule 303, where the base station 105 mayreschedule data from mini-slot 305-a into one of the mini-slots 305-bthrough 305-f, or into slot 310-b. Additionally or alternatively, thebase station 105 may also prepare data to signal the beginning ofslot-based transmissions before mini-slot 305-f, where mini-slot 305-fmay be the last mini-slot based transmission. As described herein, asignal to indicate the beginning of slot-based transmissions may be adedicated signal within one of mini-slots 305-b through 305-e, or may bea dedicated signal at a beginning of mini-slot 305-f. Additionally oralternatively, the signal to indicate the beginning of slot-basedtransmissions may be included in one of PDCCHs 315-b through 315-f. Inother cases, the base station 105 and the UE 115 may implicitlydetermine how many mini-slots 305 may follow the first mini-slottransmission based on a shared configuration (e.g., implemented via RRCsignaling or communications standards). In some cases, mini-slot 305-fmay include more resources than other mini-slots 305, based on the endof mini-slot based transmissions.

In some cases, the base station 105 may have capabilities that supportthe implementation of resource schedule 304, where the base station 105may reschedule data from mini-slot 305-a into one of mini-slots 305-bthrough 305-g, or slot 310-b. Additionally or alternatively, the basestation 105 may also prepare data to signal the beginning of slot-basedtransmissions before slot 310-b, where mini-slot 305-g may be the lastmini-slot based transmission. As discussed herein, a signal to indicatethe beginning of slot-based transmissions may be a dedicated signalwithin one of mini-slots 305-b through 305-g, or a dedicated signal atthe beginning of slot 310-b. In some cases, reception of a dedicatedsignal may indicate that the base station 105 is to transmit thesubsequent slot 310-b using slot-based transmissions, where a remainderof a current slot 310 may still be partitioned into mini-slots 305.Additionally or alternatively, the signal to indicate the beginning ofslot-based transmissions may be included in one of PDCCHs 315-b through315-h. In other cases, the base station 105 and the UE 115 mayimplicitly determine how many mini-slots 305 may follow the firstmini-slot transmission based on a shared configuration (e.g.,implemented via RRC signaling or communications standards).

In some cases, the base station 105 may transmit multiple grants formultiple UEs corresponding to mini-slots 305 using PDCCH in a samecontrol region. In some examples, a PDCCH 315 associated with amini-slot 305 may correspond to a respective control monitoring patternof a limit of blind decodes or CCEs for the UE 115 to process. In someexamples, a PDCCH limit associated with a slot 310 may also correspondto a limit of blind decodes or CCEs for the UE 115 to process. In somecases, the UE 115 may follow a control monitoring pattern that splitsthe per slot limit of CCEs or blind decodes across mini-slots 305 (e.g.,mini-slots 305 between boundaries 320 of the same slot). In someexamples, the UE 115 may split the per slot limit equally among themini-slots 305 within the slot 310. Additionally or alternatively, theUE 115 may split the per slot limit among the mini-slots 305 inproportion to a number of symbols allocated to each mini-slot 305, whencompared to a number of symbols allocated to the entire slot 310. Insome cases, if the limit is split according to the number of symbols,the process may also involve a rounding, a floor, or a ceiling operationto eliminate a decimal portion of a calculated mini-slot PDCCH limit. Inthe case where mini-slot scheduling may end before a last mini-slot ofthe slot (e.g., resulting in a larger mini-slot 305), the remaininglimit may be allocated to the remaining portion of the slot (e.g., tothe larger mini-slot 305). In some cases, the UE 115 may ensure that thesum of the limits for mini-slot PDCCHs 315 within slot boundaries 320 isless than or equal to the per slot limit for the same slot boundaries320.

For example, the UE 115 may be configured with a limit of 44 blinddecodes per slot 310 (e.g., for a sub-carrier spacing of 15 kHz) and maybe configured with four mini-slots 305 per slot 310 (e.g., as inresource schedule 302 or 304). Additionally, the UE 115 may beconfigured with four symbols in the first two mini-slots 305 following aslot boundary 320 and with three symbols in the last two mini-slots 305(e.g., leading up to a slot boundary 320). In the case where the perslot limit is split equally between mini-slot PDCCHs 315, the UE 115 maymonitor each mini-slot PDCCH 315 for 11 blind decodes each. Additionallyor alternatively, the amount of blind decodes for each mini-slot 305 maybe found by multiplying the per slot limit (e.g., 44 blind decodes) bythe fraction of the symbols that a mini-slot 305 uses out of the wholeslot 310, then performing a rounding operation. For example, in the caseof a mini-slot with four symbols (e.g., mini-slot 305-b), the per slotlimit may be multiplied by 4/14, and then a rounding operation may beperformed, which may result in a mini-slot limit of 13 blind decodes.Similarly, a mini-slot 305 with three symbols (e.g., mini-slot 305-c)may be assigned a limit of 9 blind decodes.

In some cases, similar operations may be performed to determine amini-slot limit of a larger mini-slot 305 (e.g., mini-slots 305-c and305-f in resource schedules 301 and 303). If the per slot limit is 44blind decodes and the mini-slot limits are divided equally, largermini-slots 305 may receive a remainder of the limits up to the next slotboundary 320. For example, mini-slot 305-c may receive 22 blind decodes(e.g., because mini-slot 305-c takes the space of two mini-slots 305)and mini-slot 305-f may receive 33 blind decodes (e.g., becausemini-slot 305-f takes the space of three mini-slots 305). Additionallyor alternatively, the per slot limit may be allocated to largermini-slots 305 based on the fraction of symbols within the largermini-slot 305 compared to the symbols for the entire slot 310. In suchcases, the process for calculating the limit for each mini-slot 305 mayfollow the same steps as detailed above, and the larger mini-slot 305may be allocated a total number limits assigned to any mini-slots 305the larger mini-slot 305 replaces.

FIG. 4 illustrates examples of resource schedules 401, 402, 403, and 404that support control channel design for shared wireless communicationsin accordance with aspects of the present disclosure. In some examples,resource schedules 401, 402, 403, and 404 may implement aspects ofwireless communications systems 100 or 200. A resource schedule 400(e.g., resource schedule 401, 402, 403, or 404) may includecommunications transmitted by a base station 105, which may be anexample of a base station 105 described with reference to FIGS. 1-3 .Additionally, a UE 115 may receive the communications transmitted by thebase station 105, which UE may be an example of a UE 115 described withreference to FIGS. 1-3 .

As mentioned above with reference to FIGS. 1-3 , the base station 105may perform a contention-based access procedure (e.g., LBT) to gainaccess to shared network resources (e.g., unlicensed spectrum),following which the base station 105 may begin transmissions to the UE115 using shortened-TTI (e.g., mini-slot) resources. In some cases, thebase station 105 may prepare a resource schedule 400 before passing theLBT procedure. For example, the base station 105 may prepare mini-slots405 for communications that are to take place with the UE 115 followingan LBT pass (e.g., at the end of LBT period 415). However, in somecases, neither the base station 105 nor the UE 115 may be aware of whenthe LBT pass may occur. Therefore, the base station 105 may modifyresource schedule 400, where the modification may be based oncapabilities of the base station 105.

Additionally, the base station 105 may determine to transmit amulti-grant PDCCH 420 as part of the resource schedule, where themulti-grant PDCCH 420 may include grant information for one or moremini-slots 405 that are also part of the resource schedule. Therefore,the base station 105 may also prepare a continuous downlink data channelacross one or more mini-slots 405, without a gap for a control region,and the UE 115 may not decode another PDCCH after a first mini-slot 405.In some cases, the base station 105 may transmit multiple grants (e.g.,for multiple UEs 115) corresponding to mini-slots 405 using PDCCH in asame control region. In some examples, a multi-grant PDCCH 420 may belocated within symbols of a PDSCH of a first mini-slot 405 after LBTperiod 415 (e.g., if the first mini-slot 405 after the LBT pass is afirst mini-slot 405-a of the slot 410, as in resource schedule 401). Insome cases, a multi-grant PDCCH 420 may be located before a firstmini-slot 405, at an end of a previously-prepared downlink data set(e.g., as in resource schedules 402, 403, and 404). A multi-grant PDCCH420 may be transmitted once after the LBT pass and may carry multiplegrants for following mini-slots 405.

In some examples, the resource grant in the multi-grant PDCCH 420 maycorrespond to the mini-slots 405 in a remaining part of the slot (e.g.,up to slot boundary 425) after the LBT pass (e.g., as shown in resourceschedules 401, 402, and 404). Additionally or alternatively, theresource grant in the multi-grant PDCCH may correspond to a number ofmini-slots 405 which may extend into a next slot (e.g., past slotboundary 425, as shown in resource schedule 403). In some cases, thelimit for CCEs or blind decodes for the multi-grant PDCCH 420 may bedetermined by the number of mini-slots 405 corresponding to themulti-grant PDCCH 420. In some examples, this process may involvetotaling the limits for each mini-slot 405, which may be calculated asdescribed herein with reference to FIG. 3 (e.g., allocating each limitto each mini-slot 405 equally or basing limits on a proportional numberof symbols included in each mini-slot 405).

In one example, the base station 105 may determine that the LBT passoccurs before mini-slot 405-a. As such, the base station 105 maydetermine to use resource schedule 401 and may transmit multi-grantPDCCH 420-a at or prior to the beginning of mini-slot 405-a. In somecases, the base station 105 may determine (e.g., based on thecapabilities of the base station 105) to transmit mini-slots 405 upuntil slot boundary 425-a and may include grants for each of thesemini-slots 405 within multi-grant PDCCH 420-a. In an example where eachslot is limited to 44 blind decodes and where slot limits are splitequally among mini-slots 405, multi-grant PDCCH 420-a may accordingly belimited to 44 blind decodes (e.g., the total of all mini-slot limits).Additionally, the base station 105 may indicate to the UE 115 thatslot-based communications are to begin with slot 410-a (e.g., viasignaling or a common configuration).

In a second example, the base station 105 may determine that the LBTpass occurs before mini-slot 405-b but not before mini-slot 405-a. Assuch, the base station 105 may determine to use resource schedule 402and may transmit multi-grant PDCCH 420-b prior to a beginning ofmini-slot 405-b. In some cases, the base station 105 may determine(e.g., based on the capabilities of the base station 105) to transmitmini-slots 405 up until slot boundary 425-a and may include grants foreach of these mini-slots 405 within multi-grant PDCCH 420-b. In anexample where each slot is limited to 44 blind decodes and where slotlimits are split equally among mini-slots 405, multi-grant PDCCH 420-bmay accordingly be limited to 33 blind decodes (e.g., the total of allmini-slot limits). Additionally, the base station 105 may indicate tothe UE 115 that slot-based communications are to begin with slot 410-a(e.g., via signaling or a common configuration).

In a third example, the base station 105 may determine that the LBT passoccurs before mini-slot 405-c but not before mini-slot 405-b. As such,the base station 105 may determine to use resource schedule 403 and maytransmit multi-grant PDCCH 420-c prior to a beginning of mini-slot405-c. In some cases, the base station 105 may determine (e.g., based onthe capabilities of the base station 105) to transmit mini-slots 405 upuntil slot boundary 425-b and may include grants for each of thesemini-slots 405 within multi-grant PDCCH 420-c. In an example where eachslot is limited to 44 blind decodes and where slot limits are splitequally among mini-slots 405, multi-grant PDCCH 420-c may accordingly belimited to 66 blind decodes (e.g., the total of all mini-slot limits).Additionally, the base station 105 may indicate to the UE 115 thatslot-based communications are to begin with slot 410-b (e.g., viasignaling or a common configuration).

In a fourth example, the base station 105 may determine that the LBTpass occurs before mini-slot 405-d but not before mini-slot 405-c. Assuch, the base station 105 may determine to use resource schedule 404and may transmit multi-grant PDCCH 420-d prior to the beginning ofmini-slot 405-d. In some cases, the base station 105 may determine(e.g., based on the capabilities of the base station 105) to transmitmini-slots 405 up until slot boundary 425-a and may include grants foreach of these mini-slots 405 within multi-grant PDCCH 420-d. In anexample where each slot is limited to 44 blind decodes and where slotlimits are split equally among mini-slots 405, multi-grant PDCCH 420-dmay accordingly be limited to 11 blind decodes (e.g., the total of allmini-slot limits). Additionally, the base station 105 may indicate tothe UE 115 that slot-based communications are to begin with slot 410-a(e.g., via signaling or a common configuration).

FIG. 5 illustrates an example of a process flow that supports controlchannel design for shared wireless communications in accordance withaspects of the present disclosure. In some examples, process flow 500may implement aspects of wireless communications systems 100 or 200.Additionally, process flow 500 may implement aspects of resourceschedules 300 or 400. Further, process flow 500 may be implemented by aUE 115-b and a base station 105-b, which may be examples of a UE 115 anda base station 105 described with reference to FIGS. 1-4 .

In the following description of the process flow 500, the operationsbetween UE 115-b and base station 105-b may be transmitted in adifferent order than the order shown, or the operations performed bybase station 105-b and UE 115-b may be performed in different orders orat different times. Some operations may also be left out of the processflow 500, or other operations may be added to the process flow 500. Itis to be understood that while base station 105-b and UE 115-b are shownperforming a number of the operations of process flow 500, any wirelessdevice may perform the operations shown.

At 505, base station 105-b may monitor a channel of a shared radiofrequency spectrum band during an LBT procedure, the channel beingassociated with communications between base station 105-b and UE 115-b.

Similarly, at 510, UE 115-b may monitor the shared radio frequencyspectrum band for a downlink control channel from base station 105-bduring a first TTI according to a first transmission mode (e.g.,mini-slot transmissions).

At 515, base station 105-b may identify a number (e.g., a maximum orlimit) of blind decodes for the downlink control channel and a number(e.g., a maximum or limit) of CCEs for the downlink control channel,where the total number of blind decodes and the number of CCEs may bedistributed among TTIs of the first transmission mode. In some cases,base station 105-b or UE 115-b may identify a number of blind decodesfor the downlink control channel and a number of CCEs for the downlinkcontrol channel.

At 520, base station 105-b may transmit a downlink control channel to UE115-b according to the first transmission mode during the first TTI,based on the monitoring of the shared spectrum performed by base station105-b. Additionally, UE 115-b may receive the downlink control channelfrom base station 105-b during the first TTI based on the monitoringperformed by UE 115-b. In some cases, base station 105-b may transmit,and UE 115-b may receive, the downlink control channel according to thefirst transmission mode during the first TTI based on a first subset ofthe total number of blind decodes and a first subset of the number ofCCEs. Additionally or alternatively, base station 105-b may transmit,and UE 115-b may receive, the downlink control channel based on theidentified number of blind decodes and the identified number of CCEs.

In some examples, the downlink control channel may indicate respectivegrants for each of a set of TTIs including a second TTI subsequent tothe first TTI. In some cases, the number of blind decodes and the numberof CCEs may be based on a number of TTIs of the set of TTIs. In someexamples, base station 105-b or UE 115-b may determine the set of TTIsbased on the monitoring of the shared spectrum. In some cases, the setof TTIs may include TTIs excluding the first TTI. Additionally, basestation 105-b may transmit the downlink control channel to UE 115-b in ashared data portion of the first TTI and may also transmit the downlinkcontrol channel to UE 115-b before a shared data portion of the secondTTI subsequent the first TTI. In some cases, base station 105-b maytransmit the downlink control channel to UE 115-b via a first subset ofthe CCEs during the first TTI and may transmit the downlink controlchannel via a second subset of the CCEs during the second TTI.

At 525, base station 105-b may transmit one or more downlink datatransmissions to UE 115-b over the set of TTIs in accordance with therespective grants.

At 530, base station 105-b may transmit the downlink control channel toUE 115-b according to the first transmission mode during a secondtransmission time interval based on a second subset of the total numberof blind decodes and a second subset of the number of CCEs. In somecases, the first subset of the total number of blind decodes and thesecond subset of the total number of blind decodes may be the same andthe first subset of the number of CCEs and the second subset of thenumber of CCEs may be the same.

At 535, base station 105-b may transmit a signaling to UE 115-bindicating a change from the first transmission mode to a secondtransmission mode (e.g., slot-based transmissions), the firsttransmission mode associated with a first TTI duration (e.g., mini-slotsor sTTIs) and the second transmission mode associated with a second TTIduration that is longer than the first TTI duration (e.g., slots). Insome cases, transmitting the signaling may include transmitting areference signal that indicates a beginning of communications accordingto the second transmission mode. In some examples of signaling using areference signal, base station 105-b may transmit the reference signalduring a first portion of the first TTI and transmit a single downlinkcontrol channel during a remaining portion of the first TTI based ontransmitting the reference signal during the first portion of the firstTTI. Additionally, UE 115-b may receive the reference signal during thefirst portion of the first TTI and monitor the shared radio frequencyspectrum band during a remaining portion of the first TTI based onreceiving the reference signal during the first portion of the firstTTI.

In other cases, transmitting the signaling may include transmitting aPDCCH to UE 115-b, the PDCCH including a switching indicator thatindicates one or more of a beginning of communications according to thesecond transmission mode or a continuation of communications accordingto the first transmission mode. Additionally or alternatively,transmitting the signaling may include transmitting an RRC message to UE115-b, the RRC message indicating a fixed number of TTIs forcommunications according to the first transmission mode before thechange from the first transmission mode to the second transmission mode.

At 540, UE 115-b may monitor the shared radio frequency spectrum bandfor the downlink control channel from base station 105-b during a secondTTI based on the signaling. In some cases, the second TTI subsequent tothe first TTI may include the beginning of communications according tothe second transmission mode.

FIG. 6 shows a block diagram 600 of a device 605 that supports controlchannel design for shared wireless communications in accordance withaspects of the present disclosure. The device 605 may be an example ofaspects of a UE 115 as described herein. The device 605 may include areceiver 610, a communications manager 615, and a transmitter 620. Thedevice 605 may also include a processor. Each of these components may bein communication with one another (e.g., via one or more buses).

The receiver 610 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to controlchannel design for shared wireless communications, etc.). Informationmay be passed on to other components of the device 605. The receiver 610may be an example of aspects of the transceiver 920 described withreference to FIG. 9 . The receiver 610 may utilize a single antenna or aset of antennas.

The communications manager 615 may monitor a shared radio frequencyspectrum band for a downlink control channel from a base station duringa first TTI according to a first transmission mode, receive, from thebase station, signaling indicating a change from the first transmissionmode to a second transmission mode, the first transmission modeassociated with a first TTI duration and the second transmission modeassociated with a second TTI duration that is longer than the first TTIduration, and monitor the shared radio frequency spectrum band for thedownlink control channel from the base station during a second TTI basedon the signaling.

The communications manager 615 may also monitor a shared radio frequencyspectrum band for a downlink control channel from a base station duringa first TTI, receive the downlink control channel from the base stationduring the first TTI based on the monitoring, the downlink controlchannel indicating respective grants for each of a set of TTIs includinga second TTI subsequent the first TTI, and receive one or more downlinkdata transmissions over the set of TTIs in accordance with therespective grants. The communications manager 615 may be an example ofaspects of the communications manager 910 described herein.

The communications manager 615, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 615, or itssub-components may be executed by a general-purpose processor, a digitalsignal process (DSP), an application-specific integrated circuit (ASIC),a field-programmable gate array (FPGA) or other programmable logicdevice, discrete gate or transistor logic, discrete hardware components,or any combination thereof designed to perform the functions describedin the present disclosure.

The communications manager 615, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 615, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 615, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

The transmitter 620 may transmit signals generated by other componentsof the device 605. In some examples, the transmitter 620 may becollocated with a receiver 610 in a transceiver module. For example, thetransmitter 620 may be an example of aspects of the transceiver 920described with reference to FIG. 9 . The transmitter 620 may utilize asingle antenna or a set of antennas.

The actions performed by the communications manager 615 as describedherein may be implemented to realize one or more potential advantages.For example, communications manager 615 may increase communicationreliability and decrease communication latency at a UE 115.Communications manager 615 may enable the UE 115 to receivetransmissions of different-sized TTIs (e.g., slots and mini-slots), andmay enable the UE 115 to switch transmission modes associated with thedifferent-sized TTIs, which may reduce transmission delays andretransmissions. Similarly, communications manager 615 may save powerand increase battery life at a UE 115 by reducing transmission delaysand retransmissions.

FIG. 7 shows a block diagram 700 of a device 705 that supports controlchannel design for shared wireless communications in accordance withaspects of the present disclosure. The device 705 may be an example ofaspects of a device 605, or a UE 115 as described herein. The device 705may include a receiver 710, a communications manager 715, and atransmitter 740. The device 705 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 710 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to controlchannel design for shared wireless communications, etc.). Informationmay be passed on to other components of the device 705. The receiver 710may be an example of aspects of the transceiver 920 described withreference to FIG. 9 . The receiver 710 may utilize a single antenna or aset of antennas.

The communications manager 715 may be an example of aspects of thecommunications manager 615 as described herein. The communicationsmanager 715 may include a monitoring manager 720, a mode changecomponent 725, a downlink control receiver 730, and a data receiver 735.The communications manager 715 may be an example of aspects of thecommunications manager 910 described herein.

The monitoring manager 720 may monitor a shared radio frequency spectrumband for a downlink control channel from a base station during a firstTTI according to a first transmission mode and monitor the shared radiofrequency spectrum band for the downlink control channel from the basestation during a second TTI based on received signaling.

The mode change component 725 may receive, from the base station,signaling indicating a change from the first transmission mode to asecond transmission mode, the first transmission mode associated with afirst TTI duration and the second transmission mode associated with asecond TTI duration that is longer than the first TTI duration.

The monitoring manager 720 may monitor a shared radio frequency spectrumband for a downlink control channel from a base station during a firstTTI.

The downlink control receiver 730 may receive the downlink controlchannel from the base station during the first TTI based on themonitoring, the downlink control channel indicating respective grantsfor each of a set of TTIs including a second TTI subsequent the firstTTI.

The data receiver 735 may receive one or more downlink datatransmissions over the set of TTIs in accordance with the respectivegrants.

The transmitter 740 may transmit signals generated by other componentsof the device 705. In some examples, the transmitter 740 may becollocated with a receiver 710 in a transceiver module. For example, thetransmitter 740 may be an example of aspects of the transceiver 920described with reference to FIG. 9 . The transmitter 740 may utilize asingle antenna or a set of antennas.

A processor of a UE 115 (for example, controlling the receiver 710, thetransmitter 740, or the transceiver 920 as described with reference toFIG. 9 ) may increase communication reliability and accuracy by enablingthe UE 115 to receive transmissions of different-sized TTIs (e.g., slotsand mini-slots) and to switch transmission modes associated with thedifferent-sized TTIs, which may reduce transmission delays andretransmissions (e.g., via implementation of system components describedwith reference to FIG. 8 ). Further, the processor of the UE 115 mayidentify one or more aspects of a downlink signaling (e.g., with respectto one or more resource schedules) to perform the processes describedherein. The processor of the UE 115 may identify resources ortransmissions corresponding to different transmission modes to savepower and increase battery life at the UE 115 (e.g., by strategicallyutilizing available resources and receiving intended transmissions).

FIG. 8 shows a block diagram 800 of a communications manager 805 thatsupports control channel design for shared wireless communications inaccordance with aspects of the present disclosure. The communicationsmanager 805 may be an example of aspects of a communications manager615, a communications manager 715, or a communications manager 910described herein. The communications manager 805 may include amonitoring manager 810, a mode change component 815, a reference signalreceiver 820, a control channel receiver 825, a downlink control manager830, a downlink control receiver 835, a data receiver 840, and a timeinterval manager 845. Each of these modules may communicate, directly orindirectly, with one another (e.g., via one or more buses).

The monitoring manager 810 may monitor a shared radio frequency spectrumband for a downlink control channel from a base station during a firstTTI according to a first transmission mode. In some examples, themonitoring manager 810 may monitor the shared radio frequency spectrumband for the downlink control channel from the base station during asecond TTI based on received signaling. In some cases, the monitoringmanager 810 may monitor a shared radio frequency spectrum band for adownlink control channel from a base station during a first TTI. In someaspects, the monitoring manager 810 may monitor the shared radiofrequency spectrum band during a remaining portion of the first TTIbased on receiving the reference signal during the first portion of thefirst TTI. In some instances, the second TTI includes the beginning ofcommunications according to a second transmission mode.

The mode change component 815 may receive, from the base station,signaling indicating a change from the first transmission mode to thesecond transmission mode, the first transmission mode associated with afirst TTI duration and the second transmission mode associated with asecond TTI duration that is longer than the first TTI duration.

The reference signal receiver 820 may receive a reference signal thatindicates a beginning of communications according to the secondtransmission mode.

The control channel receiver 825 may receive a PDCCH from the basestation, the PDCCH including a switching indicator that indicates one ormore of a beginning of communications according to the secondtransmission mode or a continuation of communications according to thefirst transmission mode. In some examples, the control channel receiver825 may receive an RRC message from the base station, the RRC messageindicating a fixed number of TTIs for communications according to thefirst transmission mode before the change from the first transmissionmode to the second transmission mode.

In some cases, the control channel receiver 825 may receive the downlinkcontrol channel according to the first transmission mode during thefirst TTI based on a first subset of the maximum number of blind decodesand a first subset of the maximum number of CCEs. In some instances, thecontrol channel receiver 825 may receive the downlink control channelaccording to the first transmission mode during the second TTI based ona second subset of the maximum number of blind decodes and a secondsubset of the maximum number of CCEs. In some cases, the first subset ofthe maximum number of blind decodes and the second subset of the maximumnumber of blind decodes are the same. In some aspects, the first subsetof the maximum number of CCEs and the second subset of the maximumnumber of CCEs are the same.

The downlink control manager 830 may identify a maximum number of blinddecodes for the downlink control channel and a maximum number of CCEsfor the downlink control channel, where the maximum total number ofblind decodes and the maximum number of CCEs are distributed among TTIsof the first transmission mode.

The downlink control receiver 835 may receive the downlink controlchannel from the base station during the first TTI based on themonitoring, the downlink control channel indicating respective grantsfor each of a set of TTIs including a second TTI subsequent the firstTTI. In some examples, the downlink control receiver 835 may receive thedownlink control channel in a shared data portion of the first TTI. Insome cases, the downlink control receiver 835 may receive the downlinkcontrol channel before a shared data portion of the second TTIsubsequent the first TTI. The downlink control receiver 835 may receivea PDCCH from the base station before reaching an end of the fixed numberof TTIs.

In some examples, the downlink control manager 830 may identify amaximum number of blind decodes for the downlink control channel and amaximum number of CCEs for the downlink control channel, where thedownlink control channel is received based on the maximum number ofblind decodes and the maximum number of CCEs. In some cases, the maximumnumber of blind decodes and the maximum number of CCEs are based on anumber of TTIs of the set of TTIs.

The data receiver 840 may receive one or more downlink datatransmissions over the set of TTIs in accordance with the respectivegrants.

The time interval manager 845 may determine the set of TTIs based on themonitoring, where the set of TTIs includes TTIs excluding the first TTI.The time interval manager 845 may also restart a timer comprising thefixed number of TTIs for communications according to the firsttransmission mode based at least in part on receiving the PDCCH beforereaching the end of the fixed number of TTIs.

FIG. 9 shows a diagram of a system 900 including a device 905 thatsupports control channel design for shared wireless communications inaccordance with aspects of the present disclosure. The device 905 may bean example of or include the components of device 605, device 705, or aUE 115 as described herein. The device 905 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including a communicationsmanager 910, an I/O controller 915, a transceiver 920, an antenna 925,memory 930, and a processor 940. These components may be in electroniccommunication via one or more buses (e.g., bus 945).

The communications manager 910 may monitor a shared radio frequencyspectrum band for a downlink control channel from a base station duringa first TTI according to a first transmission mode, receive, from thebase station, signaling indicating a change from the first transmissionmode to a second transmission mode, the first transmission modeassociated with a first TTI duration and the second transmission modeassociated with a second TTI duration that is longer than the first TTIduration, and monitor the shared radio frequency spectrum band for thedownlink control channel from the base station during a second TTI basedon the signaling.

The communications manager 910 may also monitor a shared radio frequencyspectrum band for a downlink control channel from a base station duringa first TTI, receive the downlink control channel from the base stationduring the first TTI based on the monitoring, the downlink controlchannel indicating respective grants for each of a set of TTIs includinga second TTI subsequent the first TTI, and receive one or more downlinkdata transmissions over the set of TTIs in accordance with therespective grants.

The I/O controller 915 may manage input and output signals for thedevice 905. The I/O controller 915 may also manage peripherals notintegrated into the device 905. In some cases, the I/O controller 915may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 915 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 915may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 915may be implemented as part of a processor. In some cases, a user mayinteract with the device 905 via the I/O controller 915 or via hardwarecomponents controlled by the I/O controller 915.

The transceiver 920 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 920 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 920may also include a modem to modulate the packets and provide themodulated packets to the antennas for transmission, and to demodulatepackets received from the antennas.

In some cases, the device 905 may include a single antenna 925, or mayhave more than one antenna 925, which may be capable of concurrentlytransmitting or receiving multiple wireless transmissions.

The memory 930 may include random access memory (RAM) and read onlymemory (ROM). The memory 930 may store computer-readable,computer-executable code 935 including instructions that, when executed,cause the processor to perform various functions described herein. Insome cases, the memory 930 may contain, among other things, a basic I/Osystem (BIOS) which may control basic hardware or software operationsuch as the interaction with peripheral components or devices.

The processor 940 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 940 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 940. The processor 940 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 930) to cause the device 905 to perform variousfunctions (e.g., functions or tasks supporting control channel designfor shared wireless communications).

The code 935 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 935 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 935 may not be directly executable by theprocessor 940 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 10 shows a block diagram 1000 of a device 1005 that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure. The device 1005 may be anexample of aspects of a base station 105 as described herein. The device1005 may include a receiver 1010, a communications manager 1015, and atransmitter 1020. The device 1005 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to controlchannel design for shared wireless communications, etc.). Informationmay be passed on to other components of the device 1005. The receiver1010 may be an example of aspects of the transceiver 1320 described withreference to FIG. 13 . The receiver 1010 may utilize a single antenna ora set of antennas.

The communications manager 1015 may monitor a channel of a shared radiofrequency spectrum band during an LBT procedure, the channel associatedwith communications between the base station and a UE, transmit adownlink control channel to the UE according to a first transmissionmode during a first TTI based on the monitoring, and transmit, to theUE, signaling indicating a change from the first transmission mode to asecond transmission mode, the first transmission mode associated with afirst TTI duration and the second transmission mode associated with asecond TTI duration that is longer than the first TTI duration.

The communications manager 1015 may also monitor a channel of a sharedradio frequency spectrum band during an LBT procedure, the channelassociated with communications between a base station and a UE, transmita downlink control channel to the UE during a first TTI based on themonitoring, the downlink control channel indicating respective grantsfor each of a set of TTIs including a second TTI subsequent the firstTTI, and transmit one or more downlink data transmissions to the UE overthe set of TTIs in accordance with the respective grants. Thecommunications manager 1015 may be an example of aspects of thecommunications manager 1310 described herein.

The communications manager 1015, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1015, or itssub-components may be executed by a general-purpose processor, a DSP, anASIC, an FPGA or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure.

The communications manager 1015, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1015, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1015, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an I/O component, atransceiver, a network server, another computing device, one or moreother components described in the present disclosure, or a combinationthereof in accordance with various aspects of the present disclosure.

The transmitter 1020 may transmit signals generated by other componentsof the device 1005. In some examples, the transmitter 1020 may becollocated with a receiver 1010 in a transceiver module. For example,the transmitter 1020 may be an example of aspects of the transceiver1320 described with reference to FIG. 13 . The transmitter 1020 mayutilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a device 1105 that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure. The device 1105 may be anexample of aspects of a device 1005, or a base station 105 as describedherein. The device 1105 may include a receiver 1110, a communicationsmanager 1115, and a transmitter 1140. The device 1105 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

The receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to controlchannel design for shared wireless communications, etc.). Informationmay be passed on to other components of the device 1105. The receiver1110 may be an example of aspects of the transceiver 1320 described withreference to FIG. 13 . The receiver 1110 may utilize a single antenna ora set of antennas.

The communications manager 1115 may be an example of aspects of thecommunications manager 1015 as described herein. The communicationsmanager 1115 may include a channel monitoring component 1120, a controlchannel transmitter 1125, a mode change transmitter 1130, and a datatransmitter 1135. The communications manager 1115 may be an example ofaspects of the communications manager 1310 described herein.

The channel monitoring component 1120 may monitor a channel of a sharedradio frequency spectrum band during an LBT procedure, the channelassociated with communications between the base station and a UE.

The control channel transmitter 1125 may transmit a downlink controlchannel to the UE according to a first transmission mode during a firstTTI based on the monitoring.

The mode change transmitter 1130 may transmit, to the UE, signalingindicating a change from the first transmission mode to a secondtransmission mode, the first transmission mode associated with a firstTTI duration and the second transmission mode associated with a secondTTI duration that is longer than the first TTI duration.

The channel monitoring component 1120 may monitor a channel of a sharedradio frequency spectrum band during an LBT procedure, the channelassociated with communications between a base station and a UE.

The control channel transmitter 1125 may transmit a downlink controlchannel to the UE during a first TTI based on the monitoring, thedownlink control channel indicating respective grants for each of a setof TTIs including a second TTI subsequent the first TTI.

The data transmitter 1135 may transmit one or more downlink datatransmissions to the UE over the set of TTIs in accordance with therespective grants.

The transmitter 1140 may transmit signals generated by other componentsof the device 1105. In some examples, the transmitter 1140 may becollocated with a receiver 1110 in a transceiver module. For example,the transmitter 1140 may be an example of aspects of the transceiver1320 described with reference to FIG. 13 . The transmitter 1140 mayutilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a communications manager 1205 thatsupports control channel design for shared wireless communications inaccordance with aspects of the present disclosure. The communicationsmanager 1205 may be an example of aspects of a communications manager1015, a communications manager 1115, or a communications manager 1310described herein. The communications manager 1205 may include a channelmonitoring component 1210, a control channel transmitter 1215, a modechange transmitter 1220, a reference signal transmitter 1225, a downlinkchannel manager 1230, a data transmitter 1235, and a time intervalmanager 1240. Each of these modules may communicate, directly orindirectly, with one another (e.g., via one or more buses).

The channel monitoring component 1210 may monitor a channel of a sharedradio frequency spectrum band during an LBT procedure, the channelassociated with communications between the base station and a UE.

The control channel transmitter 1215 may transmit a downlink controlchannel to the UE according to a first transmission mode during a firstTTI based on the monitoring. In some examples, the control channeltransmitter 1215 may transmit a downlink control channel to the UEduring a first TTI based on the monitoring, the downlink control channelindicating respective grants for each of a set of TTIs including asecond TTI subsequent the first TTI. In some cases, the control channeltransmitter 1215 may transmit a single downlink control channel during aremaining portion of the first TTI based on transmitting the referencesignal during the first portion of the first TTI. In some aspects, thecontrol channel transmitter 1215 may transmit a PDCCH to the UE, thePDCCH including a switching indicator that indicates one or more of abeginning of communications according to the second transmission mode ora continuation of communications according to the first transmissionmode. In some instances, the control channel transmitter 1215 maytransmit an RRC message to the UE, the RRC message indicating a fixednumber of TTIs for communications according to the first transmissionmode before the change from the first transmission mode to the secondtransmission mode.

In some examples, the control channel transmitter 1215 may transmit thedownlink control channel according to the first transmission mode duringthe first TTI based on a first subset of the maximum number of blinddecodes and a first subset of the maximum number of CCEs. In some cases,the control channel transmitter 1215 may transmit the downlink controlchannel according to the first transmission mode during a second TTIsubsequent the first TTI based on a second subset of the maximum numberof blind decodes and a second subset of the maximum number of CCEs. Insome aspects, the control channel transmitter 1215 may transmit thedownlink control channel in a shared data portion of the first TTI. Insome instances, the control channel transmitter 1215 may transmit thedownlink control channel before a shared data portion of the second TTIsubsequent the first TTI.

In some examples, the control channel transmitter 1215 may transmit thedownlink control channel via a first subset of the CCEs during the firstTTI. In some case, the control channel transmitter 1215 may transmit thedownlink control channel via a second subset of the CCEs during thesecond TTI. In some aspects, the first subset of the maximum number ofblind decodes and the second subset of the maximum number of blinddecodes are the same. In some instances, the first subset of the maximumnumber of CCEs and the second subset of the maximum number of CCEs arethe same.

The mode change transmitter 1220 may transmit, to the UE, signalingindicating a change from the first transmission mode to a secondtransmission mode, the first transmission mode associated with a firstTTI duration and the second transmission mode associated with a secondTTI duration that is longer than the first TTI duration.

The data transmitter 1235 may transmit one or more downlink datatransmissions to the UE over the set of TTIs in accordance with therespective grants.

The reference signal transmitter 1225 may transmit a reference signalthat indicates a beginning of communications according to the secondtransmission mode. In some examples, the reference signal transmitter1225 may transmit the reference signal during a first portion of thefirst TTI. In some cases, a second TTI subsequent the first TTI includesthe beginning of communications according to the second transmissionmode.

The downlink channel manager 1230 may identify a maximum number of blinddecodes for the downlink control channel and a maximum number of CCEsfor the downlink control channel, where the maximum number of blinddecodes and the maximum number of CCEs are distributed among TTIs of thefirst transmission mode.

In some examples, the downlink channel manager 1230 may identify amaximum number of blind decodes for the downlink control channel and aset of CCEs for the downlink control channel, where the downlink controlchannel is transmitted based on the maximum number of blind decodes andthe set of CCEs. In some cases, the maximum number of blind decodes andthe set of CCEs are based on a number of TTIs of the set of TTIs.

The time interval manager 1240 may determine the set of TTIs based onthe monitoring, where the set of TTIs includes TTIs excluding the firstTTI.

FIG. 13 shows a diagram of a system 1300 including a device 1305 thatsupports control channel design for shared wireless communications inaccordance with aspects of the present disclosure. The device 1305 maybe an example of or include the components of device 1005, device 1105,or a base station 105 as described herein. The device 1305 may includecomponents for bi-directional voice and data communications includingcomponents for transmitting and receiving communications, including acommunications manager 1310, a network communications manager 1315, atransceiver 1320, an antenna 1325, memory 1330, a processor 1340, and aninter-station communications manager 1345. These components may be inelectronic communication via one or more buses (e.g., bus 1350).

The communications manager 1310 may monitor a channel of a shared radiofrequency spectrum band during an LBT procedure, the channel associatedwith communications between the base station and a UE, transmit adownlink control channel to the UE according to a first transmissionmode during a first TTI based on the monitoring, and transmit, to theUE, signaling indicating a change from the first transmission mode to asecond transmission mode, the first transmission mode associated with afirst TTI duration and the second transmission mode associated with asecond TTI duration that is longer than the first TTI duration.

The communications manager 1310 may also monitor a channel of a sharedradio frequency spectrum band during an LBT procedure, the channelassociated with communications between a base station and a UE, transmita downlink control channel to the UE during a first TTI based on themonitoring, the downlink control channel indicating respective grantsfor each of a set of TTIs including a second TTI subsequent the firstTTI, and transmit one or more downlink data transmissions to the UE overthe set of TTIs in accordance with the respective grants.

The network communications manager 1315 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 1315 may manage the transferof data communications for client devices, such as one or more UEs 115.

The transceiver 1320 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1320 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1320 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the device 1305 may include a single antenna 1325, ormore than one antenna 1325, which may be capable of concurrentlytransmitting or receiving multiple wireless transmissions.

The memory 1330 may include RAM, ROM, or a combination thereof. Thememory 1330 may store computer-readable code 1335 including instructionsthat, when executed by a processor (e.g., the processor 1340) cause thedevice to perform various functions described herein. In some cases, thememory 1330 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1340 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1340 may be configured to operate a memoryarray using a memory controller. In some cases, a memory controller maybe integrated into processor 1340. The processor 1340 may be configuredto execute computer-readable instructions stored in a memory (e.g., thememory 1330) to cause the device 1305 to perform various functions(e.g., functions or tasks supporting control channel design for sharedwireless communications).

The inter-station communications manager 1345 may manage communicationswith other base station 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager1345 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager1345 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The code 1335 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1335 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1335 may not be directly executable by theprocessor 1340 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 14 shows a flowchart illustrating a method 1400 that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure. The operations of method 1400may be implemented by a UE 115 or its components as described herein.For example, the operations of method 1400 may be performed by acommunications manager as described with reference to FIGS. 6 through 9. In some examples, a UE may execute a set of instructions to controlthe functional elements of the UE to perform the functions describedbelow. Additionally or alternatively, a UE may perform aspects of thefunctions described below using special-purpose hardware.

At 1405, the UE may monitor a shared radio frequency spectrum band for adownlink control channel from a base station during a first TTIaccording to a first transmission mode. The operations of 1405 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1405 may be performed by a monitoringmanager as described with reference to FIGS. 6 through 9 .

At 1410, the UE may receive, from the base station, signaling indicatinga change from the first transmission mode to a second transmission mode,the first transmission mode associated with a first TTI duration and thesecond transmission mode associated with a second TTI duration that islonger than the first TTI duration. The operations of 1410 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1410 may be performed by a mode changecomponent as described with reference to FIGS. 6 through 9 .

At 1415, the UE may monitor the shared radio frequency spectrum band forthe downlink control channel from the base station during a second TTIbased on the signaling. The operations of 1415 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1415 may be performed by a monitoring manager asdescribed with reference to FIGS. 6 through 9 .

FIG. 15 shows a flowchart illustrating a method 1500 that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure. The operations of method 1500may be implemented by a base station 105 or its components as describedherein. For example, the operations of method 1500 may be performed by acommunications manager as described with reference to FIGS. 10 through13 . In some examples, a base station may execute a set of instructionsto control the functional elements of the base station to perform thefunctions described below. Additionally or alternatively, a base stationmay perform aspects of the functions described below usingspecial-purpose hardware.

At 1505, the base station may monitor a channel of a shared radiofrequency spectrum band during an LBT procedure, the channel associatedwith communications between the base station and a UE. The operations of1505 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1505 may be performed by achannel monitoring component as described with reference to FIGS. 10through 13 .

At 1510, the base station may transmit a downlink control channel to theUE according to a first transmission mode during a first TTI based onthe monitoring. The operations of 1510 may be performed according to themethods described herein. In some examples, aspects of the operations of1510 may be performed by a control channel transmitter as described withreference to FIGS. 10 through 13 .

At 1515, the base station may transmit, to the UE, signaling indicatinga change from the first transmission mode to a second transmission mode,the first transmission mode associated with a first TTI duration and thesecond transmission mode associated with a second TTI duration that islonger than the first TTI duration. The operations of 1515 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1515 may be performed by a mode changetransmitter as described with reference to FIGS. 10 through 13 .

FIG. 16 shows a flowchart illustrating a method 1600 that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure. The operations of method 1600may be implemented by a UE 115 or its components as described herein.For example, the operations of method 1600 may be performed by acommunications manager as described with reference to FIGS. 6 through 9. In some examples, a UE may execute a set of instructions to controlthe functional elements of the UE to perform the functions describedbelow. Additionally or alternatively, a UE may perform aspects of thefunctions described below using special-purpose hardware.

At 1605, the UE may monitor a shared radio frequency spectrum band for adownlink control channel from a base station during a first TTI. Theoperations of 1605 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1605 may beperformed by a monitoring manager as described with reference to FIGS. 6through 9 .

At 1610, the UE may receive the downlink control channel from the basestation during the first TTI based on the monitoring, the downlinkcontrol channel indicating respective grants for each of a set of TTIsincluding a second TTI subsequent the first TTI. The operations of 1610may be performed according to the methods described herein. In someexamples, aspects of the operations of 1610 may be performed by adownlink control receiver as described with reference to FIGS. 6 through9 .

At 1615, the UE may receive one or more downlink data transmissions overthe set of TTIs in accordance with the respective grants. The operationsof 1615 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1615 may be performed by adata receiver as described with reference to FIGS. 6 through 9 .

FIG. 17 shows a flowchart illustrating a method 1700 that supportscontrol channel design for shared wireless communications in accordancewith aspects of the present disclosure. The operations of method 1700may be implemented by a base station 105 or its components as describedherein. For example, the operations of method 1700 may be performed by acommunications manager as described with reference to FIGS. 10 through13 . In some examples, a base station may execute a set of instructionsto control the functional elements of the base station to perform thefunctions described below. Additionally or alternatively, a base stationmay perform aspects of the functions described below usingspecial-purpose hardware.

At 1705, the base station may monitor a channel of a shared radiofrequency spectrum band during an LBT procedure, the channel associatedwith communications between a base station and a UE. The operations of1705 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1705 may be performed by achannel monitoring component as described with reference to FIGS. 10through 13 .

At 1710, the base station may transmit a downlink control channel to theUE during a first TTI based on the monitoring, the downlink controlchannel indicating respective grants for each of a set of TTIs includinga second TTI subsequent the first TTI. The operations of 1710 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1710 may be performed by a control channeltransmitter as described with reference to FIGS. 10 through 13 .

At 1715, the base station may transmit one or more downlink datatransmissions to the UE over the set of TTIs in accordance with therespective grants. The operations of 1715 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1715 may be performed by a data transmitter as describedwith reference to FIGS. 10 through 13 .

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned herein as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell maybe associated with a lower-powered base station, as compared with amacro cell, and a small cell may operate in the same or different (e.g.,licensed, unlicensed, etc.) frequency bands as macro cells. Small cellsmay include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs with service subscriptionswith the network provider. A femto cell may also cover a smallgeographic area (e.g., a home) and may provide restricted access by UEshaving an association with the femto cell (e.g., UEs in a closedsubscriber group (CSG), UEs for users in the home, and the like). An eNBfor a macro cell may be referred to as a macro eNB. An eNB for a smallcell may be referred to as a small cell eNB, a pico eNB, a femto eNB, ora home eNB. An eNB may support one or multiple (e.g., two, three, four,and the like) cells, and may also support communications using one ormultiple component carriers.

The wireless communications systems described herein may supportsynchronous or asynchronous operation. For synchronous operation, thebase stations may have similar frame timing, and transmissions fromdifferent base stations may be approximately aligned in time. Forasynchronous operation, the base stations may have different frametiming, and transmissions from different base stations may not bealigned in time. The techniques described herein may be used for eithersynchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude RAM, ROM, electrically erasable programmable ROM (EEPROM), flashmemory, compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include CD, laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. An apparatus for wireless communications at auser equipment (UE), comprising: at least one processor; at least onememory coupled with the at least one processor; and instructions storedin the at least one memory and executable by the at least one processorto cause the apparatus to: monitor, in accordance with a first controlmonitoring pattern, for a downlink control channel in each transmissiontime interval of a first plurality of transmission time intervals, eachtransmission time interval of the first plurality of transmission timeintervals having a first duration, wherein the first control monitoringpattern is associated with a first quantity of blind decodes for the UE;receive, while monitoring for the downlink control channel in accordancewith the first control monitoring pattern, a physical downlink controlchannel comprising switching indicator that indicates a switch from thefirst control monitoring pattern to a second control monitoring patternthat is different from the first control monitoring pattern and isassociated with a second quantity of blind decodes for the UE, whereinthe switching indicator indicates the switch is to occur after aquantity of a third plurality of transmission time intervals; switchfrom the first control monitoring pattern to the second controlmonitoring pattern after a time period based at least in part on thequantity of the third plurality of transmission time intervals; andmonitor, after performing the switch from the first control monitoringpattern to the second control monitoring pattern, for a second downlinkcontrol channel in each transmission time interval of a second pluralityof transmission time intervals in accordance with the second controlmonitoring pattern, each transmission time interval of the secondplurality of transmission time intervals having a second duration thatis different from the first duration.
 2. The apparatus of claim 1,wherein the switching indicator indicates a beginning of communicationsaccording to the second control monitoring pattern.
 3. The apparatus ofclaim 1, wherein the instructions are further executable by the at leastone processor to cause the apparatus to: receive a radio resourcecontrol (RRC) message, the RRC message comprising an indication of afixed quantity of transmission time intervals for communicationsaccording to the first control monitoring pattern before the switch fromthe first control monitoring pattern to the second control monitoringpattern, wherein the quantity of the third plurality of transmissiontime intervals is based at least in part on the fixed quantity.
 4. Theapparatus of claim 3, wherein the instructions are further executable bythe at least one processor to cause the apparatus to: receive thephysical downlink control channel before reaching an end of the fixedquantity of transmission time intervals; and restart a timer comprisingthe fixed quantity of transmission time intervals for communicationsaccording to the first control monitoring pattern based at least in parton receiving the physical downlink control channel before reaching theend of the fixed quantity of transmission time intervals.
 5. Theapparatus of claim 1, wherein the instructions are further executable bythe at least one processor to cause the apparatus to: monitor for thedownlink control channel during a remaining portion of the first controlmonitoring pattern based at least in part on receiving the physicaldownlink control channel during a first portion of the first controlmonitoring pattern and the quantity of the third plurality oftransmission time intervals.
 6. The apparatus of claim 1, wherein thesecond control monitoring pattern comprises a beginning ofcommunications according to a second transmission mode.
 7. The apparatusof claim 1, wherein the instructions are further executable by the atleast one processor to cause the apparatus to: identify a maximumquantity of blind decodes for the downlink control channel and a maximumquantity of control channel elements (CCEs) for the downlink controlchannel, wherein the maximum quantity of blind decodes and the maximumquantity of CCEs are distributed among transmission time intervals ofthe first control monitoring pattern.
 8. The apparatus of claim 7,wherein the instructions are further executable by the at least oneprocessor to cause the apparatus to: receive the downlink controlchannel according to the first control monitoring pattern based at leastin part on a first subset of the maximum quantity of blind decodes and afirst subset of the maximum quantity of CCEs; and receive the downlinkcontrol channel according to the second control monitoring pattern basedat least in part on a second subset of the maximum quantity of blinddecodes and a second subset of the maximum quantity of CCEs.
 9. Theapparatus of claim 1, wherein one or both of the first controlmonitoring pattern and the second control monitoring pattern indicates aperiodicity for monitoring for the downlink control channel.
 10. Anapparatus for wireless communications at a network device, comprising:at least one processor; at least one memory coupled with the at leastone processor; and instructions stored in the at least one memory andexecutable by the at least one processor to cause the apparatus to:monitor a channel during a listen before talk procedure, the channelassociated with communications between the network device and a userequipment (UE); transmit, based at least in part on the monitoring andin accordance with a first control monitoring pattern, a downlinkcontrol channel in each transmission time interval of a first pluralityof transmission time intervals, each transmission time interval of thefirst plurality of transmission time intervals having a first duration,wherein the first control monitoring pattern is associated with a firstnumber of control channel elements (CCEs) for the UE; transmit, inaccordance with the first control monitoring pattern, a physicaldownlink control channel comprising a switching indicator that indicatesa switch from the first control monitoring pattern to a second controlmonitoring pattern that is different from the first control monitoringpattern and is associated with a second quantity of CCEs, wherein theswitching indicator indicates the switch is to occur after a quantity ofa third plurality of transmission time intervals; determine a timeperiod before the switch from the first control monitoring pattern tothe second control monitoring pattern based at least in part on thequantity of the third plurality of transmission time intervals; andtransmit, after the time period and in accordance with the secondcontrol monitoring pattern, the downlink control channel in eachtransmission time interval of a second plurality of transmission timeintervals, each transmission time interval of the second plurality oftransmission time intervals having a second duration that is differentfrom the first duration.
 11. The apparatus of claim 10, wherein theswitching indicator indicates a beginning of communications according tothe second control monitoring pattern.
 12. The apparatus of claim 10,wherein the instructions are further executable by the at least oneprocessor to cause the apparatus to: transmit a radio resource control(RRC) message, the RRC message indicating a fixed quantity oftransmission time intervals for communications according to the firstcontrol monitoring pattern before the switch from the first controlmonitoring pattern to the second control monitoring pattern, wherein thequantity of the third plurality of transmission time intervals is basedat least in part on the fixed quantity.
 13. The apparatus of claim 12,wherein the instructions are further executable by the at least oneprocessor to cause the apparatus to: identify a maximum quantity of CCEsfor the downlink control channel, wherein the maximum quantity of CCEsare distributed among transmission time intervals of the first controlmonitoring pattern.
 14. The apparatus of claim 13, wherein theinstructions are further executable by the at least one processor tocause the apparatus to: transmit the downlink control channel accordingto the first control monitoring pattern based at least in part on afirst subset of the maximum quantity of CCEs; and transmit the downlinkcontrol channel according to the second control monitoring patternsubsequent the first control monitoring pattern based at least in parton a second subset of the maximum quantity of CCEs.
 15. The apparatus ofclaim 10, wherein the instructions to transmit the downlink controlchannel are further executable by the at least one processor to causethe apparatus to: transmit the downlink control channel during aremaining portion of the first control monitoring pattern based at leastin part on transmitting the physical downlink control channel during afirst portion of the first control monitoring pattern.
 16. The apparatusof claim 10, wherein the second control monitoring pattern is subsequentthe first control monitoring pattern and comprises a beginning ofcommunications according to a second transmission mode.
 17. Theapparatus of claim 10, wherein one or both of the first controlmonitoring pattern and the second control monitoring pattern indicates aperiodicity for monitoring for the downlink control channel.
 18. Amethod for wireless communications at a user equipment (UE), comprising:monitoring, in accordance with a first control monitoring pattern, for adownlink control channel in each transmission time interval of a firstplurality of transmission time intervals, each transmission timeinterval of the first plurality of transmission time intervals having afirst duration, wherein the first control monitoring pattern isassociated with a first quantity of blind decodes for the UE; receiving,while monitoring for the downlink control channel in accordance with thefirst control monitoring pattern, a physical downlink control channelcomprising switching indicator that indicates a switch from the firstcontrol monitoring pattern to a second control monitoring pattern thatis different from the first control monitoring pattern and is associatedwith a second quantity of blind decodes for the UE, wherein theswitching indicator indicates the switch is to occur after a quantity ofa third plurality of transmission time intervals; switching from thefirst control monitoring pattern to the second control monitoringpattern after a time period based at least in part on the quantity ofthe third plurality of transmission time intervals ; and monitoring,after performing the switch from the first control monitoring pattern tothe second control monitoring pattern, for a second downlink controlchannel in each transmission time interval of a second plurality oftransmission time intervals in accordance with the second controlmonitoring pattern, each transmission time interval of the secondplurality of transmission time intervals having a second duration thatis different from the first duration.
 19. The method of claim 18,wherein the switching indicator indicates a beginning of communicationsaccording to the second control monitoring pattern.
 20. The method ofclaim 18, further comprising: receiving a radio resource control (RRC)message, the RRC message comprising an indication of a fixed quantity oftransmission time intervals for communications according to the firstcontrol monitoring pattern before the switch from the first controlmonitoring pattern to the second control monitoring pattern, wherein thequantity of the third plurality of transmission time intervals is basedat least in part on the fixed quantity.
 21. The method of claim 20,further comprising: receiving the physical downlink control channelbefore reaching an end of the fixed quantity of transmission timeintervals; and restarting a timer comprising the fixed quantity oftransmission time intervals for communications according to the firstcontrol monitoring pattern based at least in part on receiving thephysical downlink control channel before reaching the end of the fixedquantity of transmission time intervals.
 22. The method of claim 18,further comprising: monitoring for the downlink control channel during aremaining portion of the first control monitoring pattern based at leastin part on receiving the physical downlink control channel during afirst portion of the first control monitoring pattern and the quantityof the third plurality of transmission time intervals.
 23. The method ofclaim 18, wherein the second control monitoring pattern comprises abeginning of communications according to a second transmission mode. 24.The method of claim 18, further comprising: identifying a maximumquantity of blind decodes for the downlink control channel and a maximumquantity of control channel elements (CCEs) for the downlink controlchannel, wherein the maximum quantity of blind decodes and the maximumquantity of CCEs are distributed among transmission time intervals ofthe first control monitoring pattern.
 25. A method for wirelesscommunications at a network device, comprising: monitoring a channelduring a listen before talk procedure, the channel associated withcommunications between the network device and a user equipment (UE);transmitting, based at least in part on the monitoring and in accordancewith a first control monitoring pattern, a downlink control channel ineach transmission time interval of a first plurality of transmissiontime intervals, each transmission time interval of the first pluralityof transmission time intervals having a first duration, wherein thefirst control monitoring pattern is associated with a first number ofcontrol channel elements (CCEs) for the UE; transmitting, in accordancewith the first control monitoring pattern, a physical downlink controlchannel comprising a switching indicator that indicates a switch fromthe first control monitoring pattern to a second control monitoringpattern that is different from the first control monitoring pattern andis associated with a second quantity of CCEs, wherein the switchingindicator indicates the switch is to occur after a quantity of a thirdplurality of transmission time intervals; determining a time periodbefore the switch from the first control monitoring pattern to thesecond control monitoring pattern based at least in part on the quantityof the third plurality of transmission time intervals; and transmitting,after the time period and in accordance with the second controlmonitoring pattern, the downlink control channel in each transmissiontime interval of a second plurality of transmission time intervals, eachtransmission time interval of the second plurality of transmission timeintervals having a second duration that is different from the firstduration.
 26. The method of claim 25, wherein the switching indicatorindicates a beginning of communications according to the second controlmonitoring pattern.
 27. The method of claim 25, further comprising:transmitting a radio resource control (RRC) message, the RRC messageindicating a fixed quantity of transmission time intervals forcommunications according to the first control monitoring pattern beforethe switch from the first control monitoring pattern to the secondcontrol monitoring pattern, wherein the quantity of the third pluralityof transmission time intervals is based at least in part on the fixedquantity.
 28. The method of claim 27, further comprising: identifying amaximum quantity of CCEs for the downlink control channel, wherein themaximum quantity of CCEs are distributed among transmission timeintervals of the first control monitoring pattern.
 29. The method ofclaim 28, further comprising: transmitting the downlink control channelaccording to the first control monitoring pattern based at least in parton a first subset of the maximum quantity of CCEs; and transmitting thedownlink control channel according to the second control monitoringpattern subsequent the first control monitoring pattern based at leastin part on a second subset of the maximum quantity of CCEs.
 30. Themethod of claim 25, wherein transmitting the downlink control channelfurther comprises: transmitting the downlink control channel during aremaining portion of the first control monitoring pattern based at leastin part on transmitting the physical downlink control channel during afirst portion of the first control monitoring pattern.